Investig Clin Urol.  2017 May;58(3):179-185. 10.4111/icu.2017.58.3.179.

Evaluation of the effect of Bernoulli maneuver on operative time during mini-percutaneous nephrolithotomy: A prospective randomized study

• Gadzhiev N
• Sergei B
• Grigoryev
• Okhunov Z
• Ganpule A
• Pisarev A
• Iskakov Y
• Petrov S

• KMID: 2388062
• DOI: http://doi.org/10.4111/icu.2017.58.3.179

Abstract

PURPOSE
To evaluate the effect of "˜Bernoulli maneuver' (bringing the access sheath to horizontal plane) on operative time and stone free rates in patients undergoing mini-percutaneous nephrolithotomy (PCNL).
MATERIALS AND METHODS
All consecutive patients with a solitary kidney stone undergoing a mini-PCNL between 2015 and 2016 were included into this study. Patients were randomized either to standard prone or control (C) group patients or to tilted prone with "˜Bernoulli maneuver' group (B) patients. Pre-, intra-, and postoperative characteristics of these 2 groups were recorded and analyzed.
RESULTS
A total of 67 patients were included in the study. Of these, 40 patients were randomized to group C and 27 to group B. The mean (95% confidence limits) stone size (mm) in group C and B was 14 (13, 15) and 13 (11, 14), respectively (p=0.26). Nephroscopy time was shorter in Bernoulli group (35 minutes vs. 23 minutes, p=1.5·10⁻⁵, and Bayes factor BF₁₀=2,340, and Cohen standardized effect size d(st)=1.2). The difference made it up 12 minutes (with 95% confidence interval from 8 to 18 minutes). There were no statistically significant differences between groups regarding white blood cell, creatinine level and stone-free status defined by computed tomography on the first postoperative day.
CONCLUSIONS
In our study the "˜Bernoulli maneuver' led to a shorter nephroscopy time in mini-PCNL. This maneuver can significantly reduce nephroscopy time and save significant amount of operative time, especially in tertiary referral centers with high-volume mini-PCNL procedures.

Keyword

Bernoulli; Nephrolithiasis; Percutaneous nephrolithotomy; Renal stone

MeSH Terms

Bays
Creatinine
Humans
Kidney Calculi
Leukocytes
Nephrolithiasis
Nephrostomy, Percutaneous
Operative Time*
Prospective Studies*
Tertiary Care Centers
Creatinine

Figure

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  Fig. 1 Patient prone strapped to the operating table.

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  Fig. 2 Standard prone (A), tilted prone (B), and tilted prone (C) with hand assistance.

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  Fig. 3 Nephroscopy time in control (C) and Bernoulli (B) groups.

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  Fig. 4 Correlations between stone size and nephroscopy time (A) and between nephroscopy time and haemoglobin drop (B). 95% confidence ellipses are shown. r, linear Pearson correlation coefficient; rS, Spearman correlation coefficient.

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